AlphaProof Nexus finds a formal cuboid irreducibility proof

For positive coprime unequal integers a and b, an AlphaProof Nexus Lean proof shows that Sharipov’s degree-eight cuboid polynomial Pₐ,ᵦ(t) is irreducible over the integers. Its route uses quartic factor analysis and an infinite descent for x⁴+34x²y²+y⁴=z².

Sources for this record

What was already known

Sharipov posed the first cuboid irreducibility conjecture in 2011. Valery Asiryan had already given an informal proof of the same result in October 2025 by an elliptic-curve route.

AI involvement AI-autonomous

The project attributes discovery of this formal proof route to autonomous AlphaProof Nexus. Codrut Grosu later reconstructed and checked its mathematical argument in full; Asiryan retains priority for the earlier result.

The project explicitly attributes discovery of this distinct formal proof route to an autonomous AlphaProof Nexus run; human publication and later deformalisation are separately credited.

Importance Modest

Provides a distinct formal and elementary proof of the first cuboid irreducibility conjecture.

Limitations

It does not settle Sharipov’s other two irreducibility conjectures or perfect-cuboid existence. The autonomous-run account comes from the project maintainers.

Technical verification Formal (Lean 4/Mathlib and Comparator + human)

The source reports a sorry-free Lean proof of the exact irreducibility statement with standard axioms. Grosu’s complete deformalisation traces and checks every lemma and tactic in the mathematical argument, documenting both machine and human checking of this proof route. Neither check grants first-result priority over Asiryan.

Formal checking

Sorry-free proof build, standard-axiom audit and exact selected-statement comparison

Checker
Lean 4 kernel and Comparator in the reported repository build
Scope
Irreducibility of Pₐ,ᵦ for positive coprime unequal integers
Basis
Reported by the linked checker
Evidence source

Formal checking

Complete deformalisation tracing every lemma and tactic step and checking logical flow

Checker
Codrut Grosu
Scope
The formal proof from quartic reduction through descent to final irreducibility
Basis
Reported by the linked checker
Evidence source

Checking a formal statement does not establish that it matches the original problem.

Human understanding Full

Grosu’s complete informal reconstruction and the published proof outline explain the quartic obstruction, infinite-descent mechanism and final factorization argument.

Correction and publication history

2026-10-18 · publication

Provides a distinct formal and elementary proof of the first cuboid irreducibility conjecture.

Read this published revision